Subsequent Event - Additional Information (Detail) (Subsequent Event [Member], GOM Deep Water Program [Member], USD $)	1 Months Ended
Oct. 31, 2014
Subsequent Event [Line Items]
Duration of exploration contract	30 months
Exploration cost	$ 319,000,000
Permitted extension period of exploration contract	12 months
Daily [Member]
Subsequent Event [Line Items]
Exploration cost	$ 350,000

Cost incurred related to the upstream oil and gas activities, such as the exploration, development, and production of crude petroleum and natural gas.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 360

-Section 25

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=6474861&loc=d3e64954-109465

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 360

-Section 25

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6474861&loc=d3e65139-109465

Name:	us-gaap_ExplorationAndProductionCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration